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wiring xlr's

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rich_gale View Drop Down
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    Posted: 07 March 2009 at 7:00pm

pin2 xlr-> rca(phono) centre pin

pin3 xlr -> rca(phono) barrel

is this right?  ouput comes from the back of a mixer via the rca's  into a crossover with xlr inputs.

cheers


Edited by rich_gale - 22 December 2010 at 10:41pm
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Joe Grime Quote  Post ReplyReply Direct Link To This Post Posted: 07 March 2009 at 7:11pm
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Post Options Post Options   Thanks (0) Thanks(0)   Quote rich_gale Quote  Post ReplyReply Direct Link To This Post Posted: 07 March 2009 at 7:28pm
cheers steve.
 
#17 looks like the right one for me.  didnt know you have to ignore the shielding and just use the red and black (red and blue in my case).
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Post Options Post Options   Thanks (0) Thanks(0)   Quote csg Quote  Post ReplyReply Direct Link To This Post Posted: 07 March 2009 at 7:56pm
In order to avoid droping 6db when going from balanced to unblanced, wire as:
 
 ( xlr) pin 2 hot - centre pin ( phono)
 ( xlr) pin 1 earth - screen ( phono)
 ( xlr) pin 3 cold - screen ( phono) 
 
so, hot to hot, and common the screen and cold at the unbalanced end. Nothing else will work correctly.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote cnics Quote  Post ReplyReply Direct Link To This Post Posted: 07 March 2009 at 9:41pm
What he said.

Don't leave any of it floating.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote rich_gale Quote  Post ReplyReply Direct Link To This Post Posted: 22 December 2010 at 10:14pm
pin2 xlr-> rca(phono) centre pin

pin3 xlr -> rca(phono) barrel

is this right?  ouput comes from the back of a mixer via the rca's  into a crossover with xlr inputs.

cheers
REFLEX ALL THE WAY.... (however, im playing with horns again...) That ok Mister Valiant? :)
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Pasi Quote  Post ReplyReply Direct Link To This Post Posted: 22 December 2010 at 10:16pm
Originally posted by csg csg wrote:

In order to avoid droping 6db when going from balanced to unblanced, wire as:
 
 ( xlr) pin 2 hot - centre pin ( phono)
 ( xlr) pin 1 earth - screen ( phono)
 ( xlr) pin 3 cold - screen ( phono) 
 
so, hot to hot, and common the screen and cold at the unbalanced end. Nothing else will work correctly.


And how does this save that 6dB?
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Post Options Post Options   Thanks (0) Thanks(0)   Quote cilla.scope Quote  Post ReplyReply Direct Link To This Post Posted: 22 December 2010 at 10:46pm
The easy remember way is to think "XLR -- xcreen, live, return"  pins 1, 2, 3

screen/xcreen is pin 1,  live is pin 2, return is pin 3.

when connecting a balanced input or output to an unbalnced thingy ... you may be able to connect the two screens together,  the two lives together and on the XLR end, connect the screen and the return (pins 1 & 3) together.

If the balanced end is any good, leaving the return (pin 3) unconnected should result in a drop of 70+db, If it only drops 6db, what you have is a very poor balanced input.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote rich_gale Quote  Post ReplyReply Direct Link To This Post Posted: 22 December 2010 at 11:22pm
to feed a LMS (with xlr in's) a signal from a mixer with only unbalanced rca outputs can i just use pins 2 and 3 on the xlr, wired to the centre pin and barrel respectively?  im really having to cain the mixer to get any real signal flickering on the front of the LMS...  makes me wonder if this is right..
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Post Options Post Options   Thanks (0) Thanks(0)   Quote kevinmcdonough Quote  Post ReplyReply Direct Link To This Post Posted: 23 December 2010 at 1:08am
hey

to explain more fully, you are changing between balanced and unbalanced, and you need different connections depending on what way you are going. Most of the replies here seem to have misunderstood you and think you are going from a balanced output to an unbalanced input.

In this case although this isn't what your looking for, for future reference, you have three pins on the balanced end and you need to somehow get them down to two pins at the unbalanced end.   The "hot" pin two of the XLR is the main signal, and so this always goes to the centre pin of the RCA (or the tip of the jack if its an unbalanced jack). 

You are then left with the shield and the inverted "cold" signal. The shield (xlr pin 1) will be connected at the XLR end and so there is no real reason to connect it at the RCA end it works just fine with one end soldered (and in some situations it is actually better to leave it only connected at one end helps stop ground loops). But you can also solder it to the barrel of the RCA doesnt really matter.

As for the "cold" signal, again you can choose. The unbalanced input cant do anything with it and if you connect it to the centre pin of the RCA it will cancel out the main signal and you will get silence, which obviously you dont want, so you can either connect it to ground and bus it away (good practice and your bet bet really) or just leave it unconnected.


BUT.........

what your looking for is to go the other way, from the unbalanced RCA to the balanced XLR. In this case, your going from two pins to three pins.
Just like before the main signal is always the main signal, so the centre pin of the RCA gets connected to the "hot" pin 2 of the XLR. No big deal.

You now have the barrel of the RCA which is connected to the shield wire. Now the point of the shield wire is to pick up any interference, radio waves or random noise and keep it away from the main signal, bus it off to earth.  But at the XLR end, pin 3 of a balanced XLR eventually gets blended into the main signal (look up what balanced is to understand why if your not sure) and so if you attach the shield wire here you have the possibility of introducing that noise that your trying to keep away back into the main signal, not good. So the barrel of the RCA should be connected through the shield wire to Pin 1, where it can get sent away to ground, and pin 3 should be left unconnected so as to not introduce anything unwanted into the signal.

k


Edited by kevinmcdonough - 23 December 2010 at 9:48am
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Post Options Post Options   Thanks (0) Thanks(0)   Quote kevinmcdonough Quote  Post ReplyReply Direct Link To This Post Posted: 23 December 2010 at 1:13am
oh and in terms of having to pump the mixer, hopefully getting the correct wire as above will sort it. if not but check that you have the correct setting if it has a +4/-10dbu input selection, and also check you haven't accidental padded down or lowered the input level somehow.

k
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audiomik View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote audiomik Quote  Post ReplyReply Direct Link To This Post Posted: 23 December 2010 at 2:12am
might be worth considering the actual circuit operation of Balanced inputs.

Firstly a 'Balanced Transformer coupled input':
for an XLR input 'hot' (XLR pin 2) is connected to one end of the center tapped primary winding of the input Transformer and 'cold' (XLR pin 3) to the other end of this same winding.
Ground (XLR pin 1) is connected to a center tap so for an unbalanced source signal in order not to short half of the input transformer winding then use pin 2 of the XLR as 'hot' and pin 3 as 'cold'. In this case there should be no connection to pin 1 of the XLR input connector. Alternatively 6dB of gain can be achieved if pin 3 of the XLR is left open circuit and pin 1 only is used for the ground/screen of the unbalanced signal source.

Secondly for an 'Electronically Balanced Input':
These circuits are normally designed to operate either as Balanced (Differential) inputs or can be used unbalanced.
For Unbalanced use, the 'hot' is used as the signal input and both 'cold' and Ground for the screen from an unbalanced source are connected together. (pins 1 and 3 on an XLR)
This is most effective since the 'cold' or 'negative' input circuitry of a differential amplifier circuit used as the input when grounded provides 6dB of additional gain for the unbalanced signal. (assuming a unity gain differential amplifier input circuit which is most commonly used in this type of application).

Hope this assists
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